Apparatus for control of subsidiary clocks



April 11, 196 7 F R I 3,313,099

APPARATUS FOR CONTROL OF SUBSIDIARY CLOCKS F'ild March 29, 1965 I s Shets-Sheet 1 IN VENTOR.

April 11, 1967 v. PFEFFER APPARATUS FOR CONTROL OF SUBSIDIARY CLOCKS Filed March 29, 1965 3 Sheets-Sheet 2 INVENTOR. /0 ufie fe 1 $6M V. PFEFFER APPARATUS FOR CONTROL OF SUBSIDIARY CLOCKS Filed March 29. 1965 April 11, 1 967 5 Sheets-Sheet 5 TO MASTER CLOCK l N VEN TOR.

United States Patent O CONTROL F SUBSIDIARY CLOCKS Vaclav Pfeffer, Prague, Czechoslovakia, assignor to Laboratorni pristroje, narodni podnik, Prague, Czechoslovakia Filed Mar. 29, 1965,,Ser. No. 443,382 Claims priority, application Czechoslovakia, Apr. 11, 1964, 2,104/64, 2,105/64 12 Claims. (Cl. 5824) This invention relates to the controlling of subsidiary clocks by means of pulses transmitted by a master clock, and particularly to subsidiary clocks controlled by pulses transmitted by a master clock, but energized by their own power supply.

The general object of the invention is a system of governing subsidiary clocks which consumes but a minimum of direct current even when thesubsidiary clock is to furnish time readings atone-second intervals, and in which the subsidiary clocks are energized by alternating current drawn from the electric lighting system.

. I Further objects will become apparent from the following description of preferred embodiments illustrated in the attached drawing in which:

FIG. 1 shows essential operating elements of a subsidiary clock of the invention in rear elevation;

FIG. 2 shows the clock, partly illustrated in FIG. 1, in side-elevational section; and

APPARATUS FOR FIGS. 3 and 4 illustrate anothersubsidiary clock of the invention in views respectively corresponding to those of FIGS. 1 and 2. Referring to the drawing in detail, and initially to FIGS. 1 and 2, there is seen a supporting frame 25 in which a shaft 1 is journaled. A driving gear 3 is fixedly fastened on the shaft 1 which rotatably supports a winding barrel 4. A spiral spring 5 is enclosed in the interior of the barrel 4 to which access may be had by threadedly removing a radial cover 6. The two ends of the spring 5 are respectively attached to the shaft 1 and the barrel 4," and provisions are made for limiting the maximum and minimum stress in the spring 5 in a known manner, not illustrated, and more fully discussed in my copendin-g United States application, Ser. No. 417,384, filed on Decem ber 10, 1964, now Patent No. 3,294,198.

The drive pinion 7 of an alternating-current motor, not otherwise shown, meshes with the gear 3, and the motor will be understood to include a unidirectional clutch which prevents backward rotation of the motor by the spring 5. A gear rim 2 on the barrel 4 meshes with a pinion 8 fixedly fastened on the minute-hand shaft 9 of" the clock. The shaft 9 carries a gear 10 and the minute hand 11 of the clock, and is connected in a conventional, non-illustrated manner, with the hour hand for driving the same.

The gear 10 meshes with a pinion 12 fixedly mounted on an escapement shaft 13 and carrying a flat bar 14 which is supported by the pinion 12 slightly off-center so that the bar has two'arms 15, 16 extending from the shaft 13 in diametrically opposite directions, the arm 16 being somewhat longer than the arm 15.' The free terminal portions of the arms 15, 16 are bent at right angles into an approximately axial direction and constitute stops respectively abuttingly engageable with the armature 17 of a polarized relay 18 in two angularly offset positions of the armature when the pinion 12 rotates about its axis.

The armature 17 is pivotally mounted between two pins 19, 20 and is magnetized by one pole of a non-illustrated permanent magnet whose other pole magnetizes the U- shaped core of the relay coils 21, 22. r

The afore-describe-d subsidiary clock is operated as follows: a

The pinion 7 turns the shaft 1 to wind the spring 5 until the stress in the spring reaches a predetermined maximum, whereby the motor is stopped in a known manner. The gear rim 2 transmits the energystored in thesp ring 5 to the shaft 9 for turning the minute hand 11 and the non-illustrated hour hand at a rate controlled by the escapement constituted by the relay 18 and the bar 14. The relay coils 21, 22 receive alternating direct current pulses'of opposite polarity from a master clock, not itself shown, which cause the armature 17 to move between the illustrated position and a second one angularly offset from the illustrated position in a clockwise direction. When the armature moves into the second position in response to a pulse of suitable polarity, it releases the abutment end of short arm 15 and abuttingly catches the end of long arm 16 after the pinion 12 has rotated through one half of a turn under the urging of the spring 5.1 The next pulse received by the coils 21, 22 causes the armature 17 to return to the illustrated position, thereby releasing the arm 16 and arresting the arm 17 after another rotation of the shaft 13 through 180. 7

The minute hand 11 moves with the shaft 13, and the tooth ratio of the pinion 12. andgear 10 is such that a 180 rotation of the pinion 12 corresponds to a 6 displacement of the gear'lll and of the minute hand 11 corresponding to one minute of time on the non-illustrated clock dial.

The force of the spring 5 is applied to all meshed gears of the clock movement while the hand 11 stands still, thereby preventing vibration of the minute hand and holding the hand in a precise position. The torque applied by the spring to the minute hand for turning the same, is thirty times greater than the torque applied to the bar 14, and the pressure exerted by the bar on the armature 17 is very small, and equal to the applied torque divided by the length of the arms 15, 16. Very little power is needed, therefore, for shifting the armature between its two positions, and the necessary displacement of the armature is very small, approximately corresponding to the thickness of the flat bar '14. The relay 18 responds reliably to pulses of very small power and very short duration. The power required for actual operation of the clock is provided by the non-illustrated alternating current motor.

A power failure in the alternating-current supply of the motor does not affect clock operation as long as operating power during the period of power failure can be provided by the spring 5. When power is'restored before the spring is fully unwound, normal spring tension is quickly restoreda The clock thus consumes only a minimal amount of direct current supplied from a battery for the control pulses. I

The modified clock shown in FIGS. 3 and 4 has a second hand shaft 101 which carries the second hand 102 and is rotatably received in the coaxial tubular minute hand shaft 103 carrying the minute hand 104. A gear 105 on the shaft 10-3 meshes with a pinion 106 fixedly mounted on a countershaft 107 which also carries a gear 108 and a four-armed'star wheel 10 9. The gear 108 meshes with a pinion 110 on an escapement shaft 111. A thin rectangular damping plate or Vane 112 and a thin bar 113 are fixedly mounted on the shaft 111. The bar 113 is the structural and functional counterpart of the afore-described bar 14, and has two arms 114, 115 of slightly different length for abutting cooperation with the armature 116 of a polarized relay 117, substantially identical with the armature 17 and relay 18 described with reference to FIG. 2. The relay coils 120, 121 are connected to a master clock. The armature 116 is mounted between pivot pins 118, 119. The permanent magnet of the polarized relay 117 has not been shown.

' trated to mesh with a gear 128 mounted on the shaft 124. The motor is equipped with a uni-directional clutch which prevents its backward rotation.

The gear 128 also meshes with a gear 130 rotatably mounted on the second-hand shaft 101, and is connected with the shaft 124 by a non-illustrated clutch of the type disclosed in my aforementioned copending application which fixedly secures the gear 128 to the shaft 124 only for winding the spring 126, but releases the gear when the spring is adequately wound.

The gear 130 is axially interposed on the shaft 101 between an axially slidable pressure plate 132 and the radial end face of a sleeve 13 3 which is fixedly fastened to the shaft 101. A compression spring 131 urges the plate 132 and the gear 130 axially toward the sleeve 133 so that the plate 132, the end face of the sleeve 13 3, and the spring 132 constitute a fraction coupling which connects the gear 130 to the shaft 101 as long as the torque to be transmitted by the coupling does not exceed a certain value.

A radially elongated stop pin 134 is fixedly attached to the sleeve 133 for abutting cooperation with the star wheel 109 as is best seen in FIG. 3.

' The clock shown in FIGS. 3 and 4 operates as follows:

The non-illustrated synchronous motor maintains the desired winding stress in the barrel spring 126. When this stress is exceeded, the gear 128 is released from the shaft 124, and continues turning the second hand 102. The spring 126 tends to turn the minute hand shaft 103, the star wheel 109, and the escapement shaft 111, but rotation of the three last-mentioned elements is possible only when a pulse from the master clock shifts the armature 116, whereupon the escapement shaft may turn through 180 under the torque transmitted from the spring 126 and against the braking effect of the vane 112.

The tooth ratios of the pinions 110, 106 and of the gears 108, 105- are selected so that one half of a revolution of the escapement shaft 111 causes or permits an angular displacement of 6 of the minute hand 104 and a quarter turn of the star wheel 109. While the minute hand and the star wheel stand still, they are held in precise positions and secured against vibration by the force of the spring 126. The spring torque applied to the bar 113 is one thirtieth of the torque applied to the minute hand shaft 103, and the contact pressure of the arms 114, 115- which must be overcome for movement of the armature 116 is minimal.

The second 'hand'102 is normally driven by the synchronous alternating-current motor represented in the drawing by the pinion 129 through the friction coupling between the gear 130 and the shaft 101. If, the motor drive of the second hand 102 moves ahead of the pulsecontrolled drive of the minute hand 104, because of poor frequency control of the AC. supply, the stop pin 134 abuts against an arm of the star wheel 109 and stops the second hand 102 in the 12 oclock position, the gear 130 turning idly between the pressure plate 132 and the sleeve 13 3 of the friction coupling. The'second hand 102 is released when synchronization between the second hand and the master clock is restored, and the star wheel 109 makes its next quarter turn in response to a pulse received by the relay 117. The deviation between the reading of the second hand and the correct time signaled by the master clock cannot accumulate over more than one minute, and therefore remains small.

revolution each minute even at the slowest expected speed of the electric drive motor.

The subsidiary clocks of the invention are controlled by synchronizing pulses which are transmitted only once every minute and thus consume a minimal amount of direct current from a battery. They are still capable of indicating time in seconds. They are driven by inexpensively available house lighting current. If that current supply should be interrupted, the second hand stops, but starts again when alternating current is again supplied. The proper position of the second hand is then restored within one minute because it is synchronized with the master clock every minute. The minute hand is driven by a spring in which energy is stored to prevent stopping of the clock during limited periods ofpower failure in the alternating-current supply.

What I claim is:

1. A master-controlled subsidiary clock comprising, in combination:

(a) a drive motor;

(b) first time indicating means;

(c) first motion-transmitting means interposed between said motor and said time indicating means for actuating the same;

(d) energy storing means;

(e) second motion transmitting means interposed between said motor and said storing means for transmitting energy of said motor to said storing means;

(f) second time indicating means;

(g) third motion transmitting means interposed between said energy storing means and said second time indicating means for actuating said second time indicating means by energy stored in said storing means;

and

(h) control means connected to said first and third motion transmitting means and responsive to electrical synchronizing pulses for controlling the synchronized actuation of said first and second time indicating means by said drive motor and by said energy storing means respectively.

2. A clock as set forth in claim 1, wherein said drive motor is a synchronous alternating-current motor, and said control means are responsive to a sequence of directcurrent pulses of alternating polarity for controlling said synchronized actuation.

3. A clock as set forth in claim 2, wherein said energy storing means includes a winding barrel and a spring in said barrel.

4. A clock as set forth in claim 2, wherein said control means include a polarized relay.

5. A clock as set forth in claim 4, wherein said relay has an armature responsive to said pulses to move between two positions, and said control means further include abutment means connected to said third motion transmitting means and engageable with said armature in one of said'positions of the latter for arresting said second time indicating means, and for releasing said third motion transmitting means for limited transmission of energy to said second time indicating means when said armature moves from said one position thereof to the other position.

6. A master-controlled subsidiary clock comprising, in

combination:

(a) a second-hand;

(b) a minute-hand;

(c) a synchronous alternating-current motor;

(d) winding barrel means including a spring;

(e) first motion transmitting means connecting said second-hand to said motor for actuation thereby;

(f) second motion transmitting means connecting said motor to said winding barrel means for winding of said spring by said motor;

(g) third motion transrnitting means connecting said winding barrel means to said minute-hand for actuation of the minute-hand by the spring, and

(h) control means operatively connected to said first and third motion transmitting means and responsive to a sequence of direct current synchronizing pulses of alternating polarity for controlling the synchronized atcuation of said hands by said motor and by said spring.

7. A clock as set forth in claim 6, wherein said control means include a shaft having an axis, connecting means connecting said shaft to said minute-hand for rotation about said axis simultaneously with movement of said minute hand, a bar member secured on said shaft for rotation therewith, abutment means on said bar member and spaced from said axis, and a relay having an armature and being responsive to said pulses for movement toward and away from a position in which said armature is capable of engaging said abutment means during rotation of said bar member for stopping said rotation.

8. A clock as set forth in claim 7, wherein said relay is polarized and said armature responds to pulses of one polarity to move toward said position, and to pulses of the opposite polarity to move away from said position into another position, said bar member having two arms extending from said axis in opposite directions and said abutment means including two abutment portions of said arms respectively nearer and farther from said axis, said abutment portions respectively abuttin-gly engaging said armature in said positions of the latter during rotation of said bar member, and being released by the armature when the same is moved away from the engaged position. 9. A clock as set forth in claim 7, wherein said control means further include rotary abutment means respectively connected to said hands for simultaneous movement therewith and for arresting said second-hand in a predetermined position until said minute-hand is actuated by said spring in response to one of said pulses.

10. A clock as set forth in claim 9, wherein said rotary abutment means include a first abutment member fixedly fastened to said second-hand for movement therewith, and a second abutment member connected to said minutehand for simultaneous rotation and engageable with said first abutment member, said first motion transmitting means including a coupling responsive to a predetermined torque for disconnecting said second-hand from said motor.

11. A clock as set forth in claim 10, wherein said second a'butment member is a wheel having a plurality of radial arms.

12. A clock as set forth in claim 11, wherein said relay is polarized and said armature responds to pulses of one polarity to move toward said position, and to pulses of the opposite polarity to .move away from said position into another position, said bar member having two arms ex- References Cited by the Examiner UNITED STATES PATENTS 273,231 2/1883 Happersberger 58-26 RICHARD B. WILKINSON, Primary Examiner.

G. F. BAKER, Assistant Examiner. 

1. A MASTER-CONTROLLED SUBSIDIARY CLOCK COMPRISING, IN COMBINATION: (A) A DRIVE MOTOR; (B) FIRST TIME INDICATING MEANS; (C) FIRST MOTION-TRANSMITTING MEANS INTERPOSED BETWEEN SAID MOTOR AND SAID TIME INDICATING MEANS FOR ACTUATING THE SAME; (D) ENERGY STORING MEANS; (E) SECOND MOTION TRANSMITTING MEANS INTERPOSED BETWEEN SAID MOTOR AND SAID STORING MEANS FOR TRANSMITTING ENERGY OF SAID MOTOR TO SAID STORING MEANS; (F) SECOND TIME INDICATING MEANS; (G) THIRD MOTION TRANSMITTING MEANS INTERPOSED BETWEEN SAID ENERGY STORING MEANS AND SAID SECOND TIME INDICATING MEANS FOR ACTUATING SAID SECOND TIME INDICATING MEANS BY ENERGY STORED IN SAID STORING MEANS; AND (H) CONTROL MEANS CONNECTED TO SAID FIRST AND THIRD MOTION TRANSMITTING MEANS AND RESPONSIVE TO ELECTRICAL SYNCHRONIZING PULSES FOR CONTROLLING THE SYNCHRONIZED ACTUATION OF SAID FIRST AND SECOND TIME INDICATING MEANS BY SAID DRIVE MOTOR AND BY SAID ENERGY STORING MEANS RESPECTIVELY. 